Hoist, especially rescue hoist

ABSTRACT

The present hoist is especially adapted for rescue operations to remove persons from elevated positions. A bolt is rigidly secured with one end to a support bracket. A rope drum is rotatably supported on said bolt by a roller locking friction clutch which permits the free rotation of the rope drum in one direction and which blocks the rope drum against rotation in the opposite direction. At least one and one half turns of rope are wound around the rope drum. Guide means are provided for guiding the rope relative to the drum. The guide means comprise an elongated guide loop shaped to partially encircle the circumference of the drum and attached to said bracket. The control end of the rope runs through this guide loop. A guide block also attached to the bracket is shaped to cooperate with the drum to provide a rope guide chamber which confines said rope turns.

United States Patent [191 Brda HOIST, ESPECIALLY RESCUE HOIST Otto Brda, Breitenau 10, D-8112 Bad Kohlgrub, Germany [22] Filed: June 27, 1973 [21] Appl. No.: 374,069

[76] Inventor:

[30] Foreign Application Priority Data June 29, 1972 Germany; 2231844 [52] US. Cl. 254/154, 254/191 [51] Int. Cl A62b 1/14 [58] Field of Search 254/150, 151, 154, 156, 254/182, 190, 191, 197; 188/65.1; 24/115 C,

115 E, 115 F,115 (1,115 1,134E

[56] References Cited UNITED STATES PATENTS I 409,511 8/1889 Slough 254/156 X 551,735 12/1895 Orrock 24/134 E 723,231 3/1903 Benedict 254/191 2,462,969 3/l949 Holliday 188/65.1

[451 Apr. 30, 1974 Primary Examiner-Robert B.- Reeves Assistant Examiner'l homas E. Kocovsky Attorney, Agent, or FirmWolfgang G. Fasse; W. W.

Roberts {57] ABSTRACT 'The present hoist is especially adapted for rescue operations to remove persons from elevated positions. A bolt is rigidly secured with one end to a support bracket. A rope drum is rotatably supported on said bolt by a roller locking friction clutch which permits the free rotation of the rope drum in one direction and which blocks the rope drum against rotation in the opposite direction. At least one and one half turns of rope are wound around the rope drum. Guide means are provided for guiding the rope relative to the drum. The guide means comprise an elongated guide loop shaped to partially encircle the circumference of the drum and attached to said bracket. The control end of the rope runs through this guide loop. A guide block also attached to the bracket is shaped to cooperate with the drum to provide a rope guide chamber which confines said rope turns.

15 Claims, 9 Drawing Figures PATENTEDAPR 30 974 3807.696 SHEET 2 0F 4 HOIST, ESPECIALLY RESCUE HOIST BACKGROUND OF THE INVENTION The present invention relates to hoists, especially rescue hoists for lowering persons or loads from a danger spot, for example buildings or cable cars or the like. Such hoists are also suitable for lifting persons or loads and include a rope drum supported on a bolt extending from a bracket by a free wheeling bearing or so called roller friction clutch which permits the rope drum to freely rotate in one direction while its rotation in the opposite direction is blocked. A rope is wound around the drum at least for one and one half turns so that a braking force is applied to the rope when it glides over the drum surface in the direction in which the drum rotation is blocked, said braking action resulting from the friction between the rope and the surface of the drum. Guide means for the rope are also secured to said bracket.

Hoisting devices as described above are known for example from my US. Pat. No. 3,703,218 granted Nov. 21, 1972. The known rope guide means include rings for guiding the rope onto and off the drum. Road guide blocks have also been employed heretofore for limiting the shifting of the rope turns along the surface of the rope drum in a longitudinal direction relative to the rope drum and to prevent that adjacent turns of rope overlap each other or tend to crawl off the rope drum by riding up on the outer flange of the rope drum.

The precise guiding of the rope under all operational conditions is important to assure the safe operation of the hoist at all times. The crawling of one rope turn on top of the other is possible in prior art devices, for ex ample, as a result of dirt on the outer surface of the rope drum which may cause different'frictional resistances along the surface of the rope drum, whereby stress bunching may be caused due to the different frictional forces which are effective on the rope. .As mentioned, the rope must be properly guided under all operational conditions and that includes the operation of the hoist not only for lifting or lowering of a person or load, but also the lifting or lowering of one rope end without any load attached thereto. The rope which moves'around the drum without a load attached to the rope end must also be prevented from shifting along the rope drum. This shifting is not entirely prevented but only limited in prior art devices. I

A further operating condition under which a precise guiding of the rope must also be assured may occur when a sudden stress is applied to the rope by the load, for example, when the load at the beginning of the roping down operation has fallen freely for a short distance. Such sudden load applications may cause an elastic yielding of the rope resulting in an instantaneous stress relief in the rope which in turn may cause the loosening of the rope turned around the drum. As a result, the rope turns may shift relative to each other. The instananeous stress relief is then followed by a load application which is just as sudden and under these operating conditions it is not certain that the rope turns will return into their desired positions.

Furthermore, it is also necessary to avoid a tangling of the rope, especially of the rope turns around the rope drum, when the hoist is not in use, for example, when it is carried in a bag to a rescue operation.

The above. described hoists may be used with their basic construction in basically two different ways,

whereby only slight modifications are to be made for switching from one operation to the other. On the one hand the hoist may be secured to a fixed point above the ground, whereby. a control end and a load end of rope extend away from the rope drum. .On the other hand, one end of the rope, in this instance the load end of the rope, may be attached to a fixed point and the load itself may be connected to the hoist bracket whereby the control. end of the rope extends'downwardly away from the rope. In this instance, the entire hoist with the load attached thereto will slide down along the rope. The precise guiding of the rope must be assured in both of these instances and the change from one type of use to the other should preferably not involve any modifications in the structural arrangement of the hoist and its rope.

In the first type of operation in which the hoist is attached toa fixed point, and the person or load is connected to the load end of the rope, the latter slides around the rope drum which is blocked against rotation by the pull applied to the load end of the' rope. The braking force applied to the rope due to the friction between the rope turns and the rope drum makes it possible to control the roping down operation by a correspondingly smaller force applied to the control end of the rope.

In the second type of use wherein the load end of the rope is attached to a fixed point, the entire hoist slides down along the rope and the person attached to the hoist may control the sliding down speed by holding on to the downwardly extending control end of the rope. In other words, the person to be roped down may control the operation himself. Heretofore, it was necessary for switching from one type of operation to the other to unthread one end of the rope and to thread it back into an additional guide ring. In the known hoists, the frictional force between the rope drum which is blocked against rotation and the rope sliding relative to the rope drum could be adjusted by varying the number of turns of rope around the rope drum. The changing of the number of turns is relatively simple. However, it may involve the possibility that the rope, while it is not taut due to a load could jam or slide off the rope drum during the changing of the number of turns.

OBJECTS OF THE INVENTION In view of the foregoing, it is the aim of the invention to achieve the following objectssingly or in combina tion:

to improve the above described prior art devices especially in such a manner that the precise guiding of the rope is assured at all times and under all operational conditions as well as when the hoist is not in use;

to provide a ropeguide loop which will guide the control end of the rope so that it may extend toward or away from the rope drum from different directions, for example, in a first direction extending substantially in parallel to the load end of the rope as heretofore, or in any direction forming an angle relative to the direction of the load end of the rope, or even in the opposite direction;

without changing the guide means and without threading the rope through different guide means;

to provide guide means for the rope, especially for the control end of the rope by means of which the frictional braking force applied to the rope may be controlled without varying the number of turns of rope around the rope drum; and

to provide a road guide block which, in combination with the surface of the rope drum will form a rope guide chamber to assure the precise guiding of the rope in any type of operation of the hoist including the roping down of a person and/or load, the raising or lowering of the load end of the rope without a load attached thereto, and lowering of the entire hoist along a rope and the storing as well as transporting of the hoist, whereby in all of these situations a tangling or jamming of the rope must definitely be prevented.

SUMMARY OF THE INVENTION According to the invention there is provided a hoisting apparatus as described above which comprises two bails arranged along a portion of the circumference of the rope drum and spaced from each other to permit the passage of the rope, said bails being located close to the circumference of the rope drum and interconnected by at least one bight, preferably two bights to form a longitudinal closed opening which is bent along a portion of the circumference of the rope drum in such a manner that one end of the rope, the so called control end of the rope may be guided relative to the rope from a direction extending substantially in parallel to the opposite end of the rope or in parallel to the vertical as well as laterally relative'to the drum whereby the control end extends substantially perpendicularly to the vertical and from a direction extending substantially opposite to that of the other end of the rope, the load end of the rope, whereby in the latter instance an additional braking or control force may be applied to the rope by the friction between the control end of the rope and a bight interconnecting said bails.

The just described arrangement according to the invention has the advantage that it is not necessary to change the number of turns of rope around the rope drum for the purpose of controlling the frictional braking force. Thus, it is now possible to provide a rope guide block which completely surrounds the rope turns on the rope drum to enclose with the latter a rope guide chamber.

The rope guide block according to the invention comprises two side members and a bridging member interconnecting the side members, whereby the rope guide block reaches over the space which is taken up on the surface of the rope drum by the turns of the rope around the rope drum.

The inwardly facing surfaces of the side members of the guide block and the outwardly facing surface of the rope drum as well as the inwardly facing surface of the bridging member of the guide block forms a rope guide chamber which has such a shape as to precisely define the position of the rope turns adjacent to each other where the rope guide block reaches over the outer surface of the rope drum.

BRIEF FIGURE DESCRIPTION In order that the invention may be clearly understood, it will now be described, by way of example, with reference to the-accompanying drawings, wherein:

FIG. 1 illustrates a perspective view of the present hoist as modifiedwith a rope guide bail according to the present invention;

FIG. 2 is a somewhat schematic view illustrating the use of the present hoist for roping down a person whereby the hoist is secured to a fixed point and the control end of the rope may extend in different directions; I

FIG. 3 illustrates schematically the other type of use of the present hoist, whereby the hoist itself slides down along the rope and the person may hold on to the control end of the rope;

FIG. 4 illustrates a side view of the apparatus according to FIG. 1 omitting the rope guide bail in order to illustrate the rope guide block according to the invention;

FIG. 5a illustrates a top plan view of the rope guide block according to FIG. 4;

FIG. 5b illustrates a side view of the present rope guide block;

FIG. 50 illustrates a perspective side view of the present guide block;

FIG. 6a illustrates a sectional view along the section line VIa-VIa as shown in FIG. 5a; and

FIG. 6b illustrates a sectional view similar to that of FIG. 6a, however along the section line VIb-VIb in FIG. 5a.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS Referring to FIG. 1 there is shown a hoist provided with rope guide means according to the invention. The hoist includes a carrier bracket or plate 1 to which is attached atone end thereof a bolt, the free end of which is covered by a cup 2. A cylindrical rope drum 3 having end flanges 4 and 5 is rotatably supported on the bolt by means of a free wheeling roller locking friction clutch which permits the free wheeling rotation of the rope drum in one direction and which blocks the rotation of the rope drum in the opposite direction. Thus, the rope drum 3 is rotatable in the direction of the arrow A and locked against rotation in the direction of the arrow B. These roller locking friction clutches or so called free wheeling bearings are known per se.

A rope 6 is wound around the circumference of the rope drum 3 between the flanges 4 and 5. At least one and one half turns of rope should be wound around the drum, however, for example two and one half turns are alsofeasible. Since the drum 3 is rotatable in the direction of the arrow A, the rope end 6' which is formed into a bight 7 may be easily lifted by pulling the rope end 6" downwardly. In this operation the rope drum 3 rotates in the direction of the arrow A. In the following text the rope end 6' shall be referred to as the load end, whereas the rope end 6" shall be referred to as the control end of the rope 6.

If, however, a person and/or a load is connected to the bight 7 of the load end 6' the rope 6 will be subjected to a downwardly directed force K. This force K can be effectively controlled or balanced by a substantially smaller force K" applied to the control end 6". Between the load representing force K and the control representing K there exists the following relationship: K X" X e wherein p. is the friction coefficient and wherein (ii is the looping or grip angle of the rope around the drum. By adjusting the force K" which is considerably smaller than the load representing force K it is possible to easily control the speed of paying out rope when lowering a person or load.

According to the present invention rope guide means are provided comprising two curved legs 8 and 9 and at least one connecting bight member, preferably two connecting bight members and 11. The legs and one bight member form a curved hairpin shape, whereby the spacing between the legs 8 and 9 is such that the rope 6 may easily pass through the bail. The legs 8 and 9 are bent in such a manner that they conform substantially to a portion of the circumference of the rope drum without interfereng with the rotation of the rope drum. However, the spacing between the guide bail and the flanges of the rope drum is small enough so as to prevent passing of the rope between the spacing. The legs 8 and 9 and the connecting bights 10 and 11 thus form a longitudinal closed loop or opening 12 which is bent along a portion of the circumference of the rope drum 3, thus forming a guide bail for the rope. The thus formed bail is secured to the bracket 1 by means of two bolts 13 and 14 which may, for ex'aple, be welded to the bail or loop. Incidentally, the bracket 1 is provided with a hole 15 for connecting the bracket to a fixed point. The hole 15 extends preferably in a plane which in turn extends perpendicularly to the bracket and longitudinally and centrally through the rotational axis of the rope drum 3. The bracket is provided with a further hole 16 which is somewhat laterally displaced relative to the hole 15 for the purpose of attaching a load to the bracket as will be described in more detail below with reference to FIG.'3.

According to the invention there is further provided a rope guide block 17 which has an outer end reaching toward the surface of the rope drum without interfering with the rotation of the rope drum. The guide block 17 reaches toward the inside of the flange 4 and close enough to the latter to confine the space so that the rope may not escape between the block and the flange. The block 17 has a bracket facing endwhich is rigidly secured to the bracket, for example by bolts.

FIG. 2 illustrates one mode of operation of the present hoist. The bracket plate 1 is secured to a fixed point 19 for example by means of a spring safety book 18. A person 20 is to be roped down from the fixed point 19 which, for example, may be part of a cable car. The person 20 is supported by a harness type of seat 21 secured to the bight 7 at the load end 6' of the rope 6. The control of the roping down speed is accomplished by applying a certain control force to the control end 6" of the rope 6 by a rescue person (not shown) but holding on to the rope end 6".

As in connection with prior art devices, the assisting person may be stationed on the ground below the person to be lowered by gradually paying out rope. According to the invention the assisting person may also be stationed at a level substantially corresponding to that of the hoisting device. In that instance, the control end of the rope would extend laterally away from the drum 3 as indicated by the double-dashedline 22. In other words, in this instance the control end 22 of the rope would extend substantially as right angles relative to the load end of the rope. This type of control of the lowering is especially advantageous where, for example, the hoist is located on a construction scaffold and where the assisting person is stationed substantially adjacent to the hoist on the scaffold. The control end of the rope may even extend substantially upwardly or even straight up as shown by the double dashed line 23. This situation may, for example, occur when a crane operator is to be rescued from his cabin. This feature of permitting the control end of the rope to extend substantially laterally away from the hoist or even straight up has the further advantage that an additional assistant is not required on the ground during the lowering down operation itself.

The control of the rope from a position above the hoist has the further advantage that the control end 23 of the rope is bent about the bight 10 of the guide bail wherebyan additional frictional braking force is ap plied to the rope as the latter slides along the bight 10.

.Thus, the paying out of the rope is substantially facilitated because the upper bight 10 may contribute a substantial proportion of the required braking force and the rope drum is accordingly relieved. Further, the additional braking force between the bight l0 and the rope makes it possible to reduce the number of turns of rope around the rope drum 3. This has the advantage that all rope guide means may be positioned so close to the flange 4 that the rope 6 is completely secured. This construction is-not only compact, but it has the advantage that the need for changing the number of turns of rope around the drum 3 has been obviated without di I minishing the wide range of use for the present hoist.

The just described advantage of providing an additional braking force at the bight 10 is especially evident in a situation in which the present hoist is used as illustrated in FIG. 3. In this situation the person 20 is connected to the bracket 1 by means of a spring safety hook 25 secured to the hole 16 in the bracket 1. The load end'6 is now connected to a fixed point 19 and runs through a ring guide which is substantially aligned longitudinally with the position of the hole 16 as shown in FIG. 3. In this type of operation the person 20 may lower himself down to the ground whereby the hoist it-- self slides along the rope 6..The control of the rope end 6" is substantially facilitated because of the frictional force produced between the rope and the bight 10. Thus, the lowering speed may easily be controlled by applying a slight pull to the rope end 6" or by releasing the rope end 6" and this may be done by the person 20 himself.

Referring to FIG. 4 there is shown a side view of the hoist according to FIG. 1 and illustrating the rope guide block 200. As in FIG. 1, the rope drum 3 is secured to the bracket 1 by means of a bolt 12 and a nut 13. The rotation of the drum 3' is again free in one direction and blocked in the opposite direction by means of a so called roller locking friction clutch. The rope drum 3 comprises a cylindrical body 121 and two flanges 122 and 123. The rope-6 is wound around the cylindrical portion 121 of the drum preferably with 2.5 turns.

The operation of the device is the same as that described with reference to FIG. 1. Thus, the rope ends 6' and 6" correspond to the respective rope ends shown in FIG. 1.

According to the invention, there is provided the rope guide bail which corresponds to the rope guide ball 10 shown in FIG. 1. However, the guide bail 100 is shown in dashed lines only in order not to obscure the illustration of the rope guide block 200 which is especially shaped in accordance with the teachings of the present invention. The guide block 200 comprises a bridging member 201 and two side members 202 and 203 extending laterally away from the bridging member toward the cylindrical surface of the rope drum. The bridging member has an extension facing toward the bracket 1. The extension is provided with threaded bores 205 and 206 for securing the guide block 200 to the bracket 1 by means of screw bolts 204.

Referring now to FIGS. a, 5b, and 5c, the inwardly facing surfaces 210 and 211 of the side members 202 and 203 of the guide block 200 are slanting relative to a plane 212 extending through the rope drum and perpendicularly to the longitudinal rotational axis of the rope drum. The plane 212 is shown by a dashed-dotted line in FIG. 5a. The slanting of these inwardly facing surfaces 210 and 211 is such that it corresponds to the slanting of the rope turns around the drum. The outwardly facing surfaces 221 and 222 of the side members 202 and 203 of the guide block are somewhat concave so that the center of curvature coincides with the axis of rotation of the rope drum. The curved shape of the surfaces 221 and 222 is best seen in FIG. 5c and it will be noted that these surfaces are concentric with the cylindrical surface 121 of the rope drum 3 so that the outwardly extending members 202 and 203 may reach as close as possible to the rope drum without interfering with its rotation, whereby the rope 6 is prevented from escaping through the gap between the cylindrical surface of the rope drum and the respective matching surface 221 or 222.

The inner surfaces 210 and 21 l and the inwardly facing surface 231 of the bridge member 201 form a rope guide chamber in cooperation with the cylindrical surface 121 of the rope drum. The inner surfaces 210 and 211 prevent a shifting of the rope turns in the direction toward the bracket 1 during the hoisting down operation when a load is attached to the load end 6' of the rope. Similarly a lateral shift away from the bracket 1 is prevented when the load end 6 is pulled up either empty or with a load. The inwardly facing surface 231 of the bridge member 201 is shaped in such a manner that it will prevent the climbing of one rope turn on top of the'other even under the most extreme operating conditions, for example, if the load should change rapidly or when the rope turn should loosen during the handling as well as during the transport of the hoist.

The shape of the inner surface 231 is best illustrated in FIG. Sc. The surface 231 is not concentric relative to the surface 221 of the rope drum. Rather, the surface 231 has a shape which will accommodate the shape of the rope turns under various load conditions. Thus, the surface 231 has a first edge 231 which slants toward the bracket 1 and a second edge 231" which slants away from the bracket 1.

In order to conform the curvature of the surface 231 to the shape of the rope turns it has been found that the spacing between certain points on the surface 231 and the respective point on the surface 121 of the drum must have a certain relationship relative to each other. The points on the surface 231 are designated as Al, A2, A3, and A4 in FIG. 5a. The respective spacings a1, a2, a3, and a4 are shown in FIGS. 6a and 6b. The relationship between these spacings will now be explained. Assuming that the rope end 6 has attached thereto a load which is being lowered, the rope 6 will slide over the rope drum in the direction of the arrows 6a, as shown in FIG. 4 since the rope drum 3 is blocked against rotation in the direction of the arrow 6a. The rope turn will enter the chamber formed between the surfaces 210, 21 l, 231, and 121, for the first time at the point A1. The rope turn will leave this chamber for the first time at the point A2. The rope turn 241 which enters the chamber at A1 and leaves the chamber at A2 is shown in FIG. 4 as well as in FIGS. 6a and 6b. The rope turn 240 which enters the chamber at the point A3 leaves the chamber for the second time at A4.

The respective spacings a1, a2, a3, and a4 should have, according to the invention, the following relationships relative to each other: a1 smaller than a2, a3 larger than a4, a3 larger than a1, and a4 smaller than a2. It has been found that at least one of these relationships should be satisfied in order to achieve a proper guiding of the rope turns. The optimal guidance, however, is achieved when all the relationships are satisfied because in that instance the curvature of the inner surface 231 of the bridging member 201 corresponds closely to the deformation of the cross section of the rope turns 240 and 241.

The different deformations of the rope 'cross section, especially inside the chamber formed by the guide block 200 are due to the different frictional forces which are effective between the rope and the surface of the rope drum as well as between the surfaces of the two turns 240 and 241 touching each other and between the inwardly facing surfaces 210 or 211 and the respective adjacent rope surfaces. Thus, if the rope is not subject to a load at all it would tend to maintain its circular cross section. As a result, the rope would be slightly squeezed inside the above mentioned chamber. This is desirable because it keeps the rope in its proper position even if no load is applied. As soon as a load is applied the slight flattening will occur at the load side of the rope.

As best seen in FIGS. 6a and 6b the side members 202 and 203 have outwardly facing surfaces which are spaced from each other so as to fit into the space between the inwardly facing surfaces of the flanges 122 and 123 without interfering with the rotation of the rope drum. In addition, the bracket facing end of the block 200 provides sufficient clearance for the flange 122.

Although the invention has been described with reference to specific example embodiments, it is to be understood, that it is intended to cover all modifications and equivalents within the scope of the appended claims.

What is claimed is:

1. In a hoisting apparatus wherein a rope drum is supported by means of a roller locking friction clutch on a bolt attached at one end thereof to a bracket, whereby the rope drum is rotatable in one direction and blocked against rotation in the opposite direction in response to pull applied to a control end or to a load end of a rope in a second operating mode wound around said rope drum at least one and one half times, said blocked rope drum providing a frictional braking force for the rope when said pull is applied to the load end of the rope, the improvement comprising rope guide means including an elongated guide bail, means for securing said elongated guide bail to said bracket, said guide bail having such a shape as to conform around part of the circumference of said rope drum, said guide bail having two legs and at least one closed bight for connecting said legs to each other at one end of the bail whereby the control end of the rope may run freely through the guide bail when the control end and the load end extend substantially in parallel or substantially at a right angle to each other, and whereby a further braking force may be applied to said control end of the rope by said bight when the two rope ends extend substantially in opposite directions.

2. The apparatus according to claim 1, wherein said guide bail comprises two bights to form a closed elongated loop.

3. The'apparatus according to claim 1, wherein said bail has the shape of a hair pin which is bent to conform to part of the circumference of the rope drum.

4. The apparatus according to claim 1, wherein said bracket comprises two sections set-off relative to each other and a slanted section interconnecting said two set-off sections so that the latter extend in two parallel planes.

5. The apparatus according to claim 1, further comprising means for securing said bracket to a fixed point.

6. The apparatus according to claim 5, wherein said securing means comprise a hole in said bracket, said hole being located so that its center axis extends substantially in parallel to said bolt and in a plane extending substantially perpendicularly to the bracket and longitudinally and centrally through said bolt.

7. The apparatus according to claim 1, further comprising means for connecting a load to said bracket.

8. The apparatus according to claim 7, wherein said load connecting means comprise a further hole in said bracket.

9. The apparatus according to claim 8, further comprising a guide ring for the load end of said rope, means for securing said guide ring to said bracket adjacent to said drum substantially opposite one end of said guide bail and substantially in alignment with said load connecting means.

10. The apparatus according to claim 1, wherein said rope guide means comprise a rope guide block, means for securing said rope guide block to said bracket in such a position that the guide block reaches fully over the rope turns on the rope drum and that the free end of the guide block reaches close enough to the free end of the rope drum to confine the rope turns on the drum.

said side members have surfaces which face each other and extend at an angle relative to a plane extending perpendicularly to said bolt through the rope drum.

13. The apparatus according to claim 11, wherein said rope drum comprises two end flanges spaced from each other by a given spacing, said side members of said guide block having outwardly facing surfaces spaced from each other to fit into said spacing between said flanges whereby the side members reach close to the surface of the rope drum without interfering with the rotation of the rope drum, said bridging member further having a bracket facing end long enough to provide clearance for the end flange of the rope drum adjacent to the bracket.

14. The apparatus according to claim 11, wherein said bridging member comprises a bottom surface facing said rope drum, said bottom surface having a shape conforming to the shape of the rope turns.

15. The apparatus according to claim 14, wherein said bottom surface of the bridging member has a first edge along its side where the rope turns enter the guide block when the rope drum is blocked, which first edge slants toward said bracket, and a second edge along its side where the rope. turns leave the guide block when the rope drum is blocked, which second edge slants away from said bracket whereby different spacings a1, a2, a3, a4 between said bottom surface and the surface of the rope drum are established, wherein a1 is the spacing at the higher end of said first edge, a2 is the spacing at the lower end of the second edge, 03 is the spacing at the lower end of the first edge, and a4 is the spacing at the higher end of the second edge, and wherein said spacings satisfy at least one of the following relationships: a1 is smaller than a2; a3 is larger than a4; a3 is larger than a1, and a4 is smaller than a2.

I} UNETED STATES PATIENT ewma CERTEFIQATE 8F CQRREGEWN Patent 'No. 3,807,696 Dated April 30, 1974 Inventor(s) OHIO Brda It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown belo wz Column 8, line 54 delete or" insert therefor --in a first operating mode, and

Signed end sealed this 24th day 0f September 197 (SEAL) Attest:

C. MARSHALL DANN MCCOY M. GIBSON JR. 1 Attesting Officer Commissioner of Patents I ORM PCP-i 050 (I 0-69) 

1. In a hoisting apparatus wherein a rope drum is supported by means of a roller locking friction clutch on a bolt attached at one end thereof to a bracket, whereby the rope drum is rotatable in one direction and blocked against rotation in the opposite direction in response to pull applied to a control end or to a load end of a rope in a second operating mode wound around said rope drum at least one and one half times, said blocked rope drum providing a frictional braking force for the rope when said pull is applied to the load end of the rope, the improvement comprising rope guide means including an elongated guide bail, means for securing said elongated guide bail to said bracket, said guide bail having such a shape as to conform around part of the circumference of said rope drum, said guide bail having two legs and at least one closed bight for connecting said legs to each other at one end of the bail whereby the control end of the rope may run freely through the guide bail when the control end and the load end extend substantially in parallel or substantially at a right angle to each other, and whereby a further braking force may be applied to said control end of the rope by said bight when the two rope ends extend substantially in opposite directions.
 2. The apparatus according to claim 1, wherein said guide bail comprises two bights to form a closed elongated loop.
 3. The apparatus according to claim 1, wherein said bail has the shape of a hair pin which is bent to conform to part of the circumference of the rope drum.
 4. The apparatus according to claim 1, wherein said bracket comprises two sections set-off relative to each other and a slanted section interconnecting said two set-off sections so that the latter extend in two parallel planes.
 5. The apparatus according to claim 1, further comprising means for securing said bracket to a fixed point.
 6. The apparatus according to claim 5, wherein said securing means comprise a hole in said bracket, said hole being located so that its center axis extends substantially in parallel to said bolt and in a plane extending substantially perpendicularly to the bracket and longitudinally and centrally through said bolt.
 7. The apparatus according to claim 1, further comprising means for connecting a load to said bracket.
 8. The apparatus according to claim 7, wherein said load connecting means comprise a further hole in said bracket.
 9. The apparatus according to claim 8, further comprising a guide ring for the load end of said rope, means for securing said guide ring to said bracket adjacent to said drum substantially opposite one end of said guide bail and substantially in alignment with said load connecting means.
 10. The apparatus according to claim 1, wherein said rope guide means comprise a rope guide block, means for securing said rope guide block to said bracket in such a position that the guide block reaches fully over the rope turns on the rope drum and that the free end of the guide block reaches close enough to the free end of the rope drum to confine the rope turns on the drum.
 11. The apparatus according to claim 10, wherein said rope guide block comprises two side members and a bridging member interconnecting said side members which face toward the rope drum surface to form with said rope drum surface a rope chamber which confines said rope turns.
 12. The apparatus according to claim 11, wherein said side members have surfaces which face each other and extend at an angle relative to a plane extending perpendicularly to said bolt through the rope drum.
 13. The apparatus according to claim 11, wherein said rope drum comprises tWo end flanges spaced from each other by a given spacing, said side members of said guide block having outwardly facing surfaces spaced from each other to fit into said spacing between said flanges whereby the side members reach close to the surface of the rope drum without interfering with the rotation of the rope drum, said bridging member further having a bracket facing end long enough to provide clearance for the end flange of the rope drum adjacent to the bracket.
 14. The apparatus according to claim 11, wherein said bridging member comprises a bottom surface facing said rope drum, said bottom surface having a shape conforming to the shape of the rope turns.
 15. The apparatus according to claim 14, wherein said bottom surface of the bridging member has a first edge along its side where the rope turns enter the guide block when the rope drum is blocked, which first edge slants toward said bracket, and a second edge along its side where the rope turns leave the guide block when the rope drum is blocked, which second edge slants away from said bracket whereby different spacings a1, a2, a3, a4 between said bottom surface and the surface of the rope drum are established, wherein a1 is the spacing at the higher end of said first edge, a2 is the spacing at the lower end of the second edge, a3 is the spacing at the lower end of the first edge, and a4 is the spacing at the higher end of the second edge, and wherein said spacings satisfy at least one of the following relationships: a1 is smaller than a2; a3 is larger than a4; a3 is larger than a1, and a4 is smaller than a2. 